js闭包的应用

     <ul id="ul1">
        <li style="border:1px solid red;">1</li>
        <li style="border:1px solid red;">2</li>
        <li style="border:1px solid red;">3</li>
     </ul>

     <div id="div1">
         <div style="background: red;height:300px;display:block;"></div>
         <div style="background: green;height:300px;display:none;"></div>
         <div style="background: blue;height:300px;display:none;"></div>
     </div>

<a href="http://www.baidu.com" target=“_blank”>link<a>

      window.onload = function(){
             var oLis = document.getElementById("ul1").getElementsByTagName('li');
             for(var i=0; i< oLis.length; i++){
                 oLis[i].onclick = (function(i){
                       return function(){
                         oDiv._change_tab(i);
                      }
                 })(i);
             }
        }

        var oDiv = {
            _change_tab: function(index){
                 var oDivs = document.getElementById("div1").getElementsByTagName("div");
                 var oCur_Slibs = oDiv._get_sliblings(oDivs[index], oDivs);
                 oDivs[index].style.display = "block";
                 for(var n=oCur_Slibs.length-1; n >= 0; n--){
                     oCur_Slibs[n].style.display = "none";
                }             
            },
            _get_sliblings: function(currentNode, childNodes){
                var slibsList = [];
                for(var n= childNodes.length-1; n>=0; n--){
                     if(childNodes[n].nodeType === 1 && childNodes[n] !== currentNode){
                          slibsList.push(childNodes[n]);
                     }
                }
                return slibsList;
            }
        }

        window.onbeforeunload =  function close(){
            var oLis = document.getElementById("ul1").getElementsByTagName('li');
            for(var n= oLis.length-1; n>=0; n--){
                oLis[i].onclick = null;
                console.log(i);
                alert(i);
            }
        }